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Chatterjee S, Mukherjee P, Sen A, Sen P. Evidence of Short-Lived High-Energy Emissive State and Triplet Character of the Self-Trapped Exciton in Cs 3Cu 2I 5 Perovskite. J Phys Chem Lett 2024; 15:4191-4196. [PMID: 38598408 DOI: 10.1021/acs.jpclett.4c00511] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/12/2024]
Abstract
Cs3Cu2I5 perovskite displays a Stokes-shifted photoluminescence (PL) at 445 nm, attributed to the self-trapped excitons (STEs). Unlike that observed in other perovskite materials, the free-exciton emission is not evidenced in this case. Herein, we reveal the existence of a short-lived high-energy emission centered around 375 nm through the reconstruction of time-resolved emission spectra (TRES), which is independent of the shape/size of Cs3Cu2I5 perovskite. This high-energy emission is proposed to originate from the free-exciton-derived distorted S1 state of the 0D Cs3Cu2I5 moiety. Moreover, STE PL (∼445 nm) was found to have phosphorescence characteristics. Theoretical calculation confirms a facile intersystem crossing at the Franck-Condon geometry, indicating the high lifetime of the STE and its triplet nature. The existence of a high-energy emissive state and the phosphorescent nature of the STE PL band provide valuable insights that could advance our understanding of the photophysics in these materials.
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Affiliation(s)
- Shovon Chatterjee
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur 208 016, U.P., India
| | - Puspal Mukherjee
- Department of Chemistry, School of Sciences, Netaji Subhas Open University, Kolkata 700 064, W.B., India
| | - Arghya Sen
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur 208 016, U.P., India
| | - Pratik Sen
- Department of Chemistry, Indian Institute of Technology Kanpur, Kanpur 208 016, U.P., India
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2
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Singh Z, Chiong JD, Kamal S, Majewski MB. Effects of increasing ligand conjugation in Cu(I) photosensitizers on NiO semiconductor surfaces. Dalton Trans 2024; 53:6367-6376. [PMID: 38497406 DOI: 10.1039/d3dt03890d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/19/2024]
Abstract
Dye-sensitized photoelectrodes may be used as heterogeneous components for fuel-forming reactions in photoelectrochemical cells. There has been increasing interest in developing Earth-abundant cheaper photosensitizers based on first-row transition metals. We describe here the synthesis, characterization, and study of the ground and excited state properties of three Cu(I) complexes bearing ligands with varying electron-accepting capacities and conjugation that may act as photosensitizers for wide bandgap semiconductors. Femtosecond transient absorption studies indicate that the nature of the final excited state is dictated by the extent of conjugation in the electron-accepting ligand, where shorter conjugation leads to the formation of a singly reduced ligand and longer conjugation leads to the formation of a ligand-centered final excited state. These complexes were surface anchored onto nanostructured NiO on conductive fluorine-doped tin oxide glass to fabricate photocathodes. It was found that even though the ligands with increasing conjugation have an effect on the formation of the final excited state in solution, all complexes exhibit similar photocurrents upon white light illumination, suggesting that charge transfer to NiO happens in advance of the formation of the final excited state.
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Affiliation(s)
- Zujhar Singh
- Department of Chemistry and Biochemistry and Centre for NanoScience Research, Concordia University, 7141 Sherbrooke Street West, Montreal, Quebec, Canada, H4B 1R6.
| | - Joseph D Chiong
- Department of Chemistry and Biochemistry and Centre for NanoScience Research, Concordia University, 7141 Sherbrooke Street West, Montreal, Quebec, Canada, H4B 1R6.
| | - Saeid Kamal
- Department of Chemistry and Laboratory for Advanced Spectroscopy and Imaging Research (LASIR), The University of British Columbia, 2036 Main Mall, Vancouver, British Columbia V6T 1Z1, Canada
| | - Marek B Majewski
- Department of Chemistry and Biochemistry and Centre for NanoScience Research, Concordia University, 7141 Sherbrooke Street West, Montreal, Quebec, Canada, H4B 1R6.
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3
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Wang LX, Cheng SC, Liu Y, Leung CF, Liu JY, Ko CC, Lau TC, Xiang J. Synthesis, structure and photoluminescence of Cu(I) complexes containing new functionalized 1,2,3-triazole ligands. Dalton Trans 2023; 52:16032-16042. [PMID: 37850402 DOI: 10.1039/d3dt02242k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2023]
Abstract
The reaction of a triazole ligand, 2-(1H-1,2,3-triazol-4-yl)pyridine (L1), with 2-bromopyridine afforded three new ligands, 2,2'-(1H-1,2,3-triazole-1,4-diyl)dipyridine (L2), 2,2'-(2H-1,2,3-triazole-2,4-diyl)dipyridine (L3) and 2,2'-(1H-1,2,3-triazole-1,5-diyl)dipyridine (L4). A series of luminescent mononuclear copper(I) complexes of these ligands [Cu(Ln)(P^P)](ClO4) [n = 1, P^P = (PPh3)2 (1); n = 1, P^P = POP (2); n = 2, P^P = (PPh3)2 (3); n = 2, P^P = POP (4); n = 3, P^P = (PPh3)2 (5); n = 3, P^P = POP (6); n = 4, P^P = (PPh3)2 (9); n = 4, P^P = POP (10)] have been obtained from the reaction of Ln with [Cu(MeCN)4]ClO4 in the presence of PPh3 and POP. L3 was also found to form dinuclear compounds [Cu2(L3)(PPh3)4](ClO4)2 (7) and [Cu2(L3)(POP)2](ClO4)2 (8). All of the Cu(I) compounds have been characterized by IR, UV/vis, CV, 1H NMR, and 31P{1H} NMR. The molecular structures of 1-3, 5, and 7 have been further determined by X-ray crystallography. In CH2Cl2 solutions, these Cu(I) complexes exhibit tunable green to orange emissions (563-621 nm) upon excitation at λex = 380 nm. In the solid state, these complexes show intense emissions and it is interesting to note that 1 and 3 are blue-light emitters. Density functional theory (DFT) calculations revealed that the lowest energy electronic transition associated with these complexes predominantly originates from metal-to-ligand charge transfer transitions (MLCT).
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Affiliation(s)
- Li-Xin Wang
- Key Laboratory of Optoelectronic Chemical Materials and Devices (Ministry of Education), School of Optoelectronic Materials and Technology, Jianghan University, Wuhan, 430056, China.
| | - Shun-Cheung Cheng
- Department of Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong, Hong Kong
| | - Yingying Liu
- Institute of Intelligent Machines, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, P. R. China
| | - Chi-Fai Leung
- Department of Science and Environmental Studies, The Education University of Hong Kong, Hong Kong, China
| | - Ji-Yan Liu
- Key Laboratory of Optoelectronic Chemical Materials and Devices (Ministry of Education), School of Optoelectronic Materials and Technology, Jianghan University, Wuhan, 430056, China.
| | - Chi-Chiu Ko
- Department of Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong, Hong Kong
| | - Tai-Chu Lau
- Department of Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong, Hong Kong
| | - Jing Xiang
- Key Laboratory of Optoelectronic Chemical Materials and Devices (Ministry of Education), School of Optoelectronic Materials and Technology, Jianghan University, Wuhan, 430056, China.
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4
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Kim D, Rosko MC, Dang VQ, Castellano FN, Teets TS. Sterically Encumbered Heteroleptic Copper(I) β-Diketiminate Complexes with Extended Excited-State Lifetimes. Inorg Chem 2023; 62:16759-16769. [PMID: 37782937 DOI: 10.1021/acs.inorgchem.3c02042] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/04/2023]
Abstract
One of the main challenges in developing effective copper(I) photosensitizers is their short excited-state lifetimes, usually attributed to structural distortion upon light excitation. We have previously introduced copper(I) charge-transfer chromophores of the general formula Cu(N^N)(ArNacNac), where N^N is a conjugated diimine ligand and ArNacNac is a substituted β-diketiminate ligand. These chromophores were promising regarding their tunable redox potentials and intense visible absorption but were ineffective as photosensitizers, presumably due to short excited-state lifetimes. Here, we introduce sterically crowded analogues of these heteroleptic chromophores with bulky alkyl substituents on the N^N and/or ArNacNac ligand. Structural analysis was combined with electrochemical and photophysical characterization, including ultrafast transient absorption (UFTA) spectroscopy to investigate the effects of the alkyl groups on the excited-state lifetimes of the complexes. The molecular structures determined by single-crystal X-ray diffraction display more distortion in the ground state as alkyl substituents are introduced into the phenanthroline or the NacNac ligand, showing smaller τ4 values due to the steric hindrance. UFTA measurements were carried out to determine the excited-state dynamics. Sterically encumbered Cu5 and Cu6 display excited-state lifetimes 15-20 times longer than unsubstituted complex Cu1, likely indicating that the incorporation of bulky alkyl substituents inhibits the pseudo-Jahn-Teller (PJT) flattening distortion in the excited state. This work suggests that the steric properties of these heteroleptic copper(I) charge-transfer chromophores can be readily modified and that the excited-state dynamics are strongly responsive to these modifications.
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Affiliation(s)
- Dooyoung Kim
- Department of Chemistry, University of Houston, Houston, Texas 77204-5003, United States
| | - Michael C Rosko
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, United States
| | - Vinh Q Dang
- Department of Chemistry, University of Houston, Houston, Texas 77204-5003, United States
| | - Felix N Castellano
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, United States
| | - Thomas S Teets
- Department of Chemistry, University of Houston, Houston, Texas 77204-5003, United States
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5
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Charette BJ, King SR, Chen J, Holm AR, Malme JT, Cook RD, Schaller RD, Jackson NE, Olshansky L. Excited State Dynamics of a Conformationally Fluxional Copper Coordination Complex. J Phys Chem A 2023; 127:7747-7755. [PMID: 37672011 DOI: 10.1021/acs.jpca.3c04269] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/07/2023]
Abstract
The conversion of solar energy into chemical fuel represents a capstone goal of the 21st century and has the potential to supply terawatts of power in a globally distributed manner. However, the disparate time scales of photodriven charge separation (∼fs) and steps in chemical reactions (∼μs) represent an inherent bottleneck in solar-to-fuels technology. To address this discrepancy, we are developing earth-abundant coordination complexes that undergo light-induced conformational rearrangements such that charge separation (CS) is hastened, while charge recombination (CR) is slowed. To these ends, we report the preparation and characterization of a new series of conformationally fluxional copper coordination complexes that contain a twisted intramolecular charge transfer (TICT) fluorophore as part of their ligand scaffold. Structural and spectroscopic characterization of the Cu(I) and Cu(II) complexes formed with these ligands in their ground states establish oxidation state-dependent conformational dynamicity, while time-resolved emission and transient absorption spectroscopies define the photophysical parameters of photo-induced excited states. Building on initial reports with a related set of molecules, the improved ligand design presented here greatly simplifies the observed photophysics, effectively shutting down unwanted ligand-centered excited states previously observed. Time-dependent density functional theory (TDDFT) analyses reveal an unusual metal-to-TICT electronic transition only reported once before, and though the formation of a CS state is not observed directly through experiments, TDDFT geometry optimizations in the excited states support the formation of transient Cu(II) CS species, lending credence to the potential success of our approach. These studies establish a clear model for the excited state dynamics at play in proof-of-concept systems and clarify key design parameters for future optimizations toward achieving long-lived CS via photoinduced conformational gating.
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Affiliation(s)
- Bronte J Charette
- University of Illinois, Urbana-Champaign, 600 S. Mathews Avenue, Urbana, Illinois 61801, United States
| | - Shelby R King
- University of Illinois, Urbana-Champaign, 600 S. Mathews Avenue, Urbana, Illinois 61801, United States
| | - Jiaqi Chen
- University of Illinois, Urbana-Champaign, 600 S. Mathews Avenue, Urbana, Illinois 61801, United States
| | - Annika R Holm
- University of Illinois, Urbana-Champaign, 600 S. Mathews Avenue, Urbana, Illinois 61801, United States
| | - Justin T Malme
- University of Illinois, Urbana-Champaign, 600 S. Mathews Avenue, Urbana, Illinois 61801, United States
| | - Robert D Cook
- University of Illinois, Urbana-Champaign, 600 S. Mathews Avenue, Urbana, Illinois 61801, United States
| | - Richard D Schaller
- Center for Nanoscale Materials, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Nicholas E Jackson
- University of Illinois, Urbana-Champaign, 600 S. Mathews Avenue, Urbana, Illinois 61801, United States
| | - Lisa Olshansky
- University of Illinois, Urbana-Champaign, 600 S. Mathews Avenue, Urbana, Illinois 61801, United States
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6
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Jouaiti A, Ballerini L, Shen HL, Viel R, Polo F, Kyritsakas N, Haacke S, Huang YT, Lu CW, Gourlaouen C, Su HC, Mauro M. Binuclear Copper(I) Complexes for Near-Infrared Light-Emitting Electrochemical Cells. Angew Chem Int Ed Engl 2023; 62:e202305569. [PMID: 37345993 DOI: 10.1002/anie.202305569] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Revised: 06/12/2023] [Accepted: 06/22/2023] [Indexed: 06/23/2023]
Abstract
Two binuclear heteroleptic CuI complexes, namely Cu-NIR1 and Cu-NIR2, bearing rigid chelating diphosphines and π-conjugated 2,5-di(pyridin-2-yl)thiazolo[5,4-d]thiazole as the bis-bidentate ligand are presented. The proposed dinuclearization strategy yields a large bathochromic shift of the emission when compared to the mononuclear counterparts (M1-M2) and enables shifting luminescence into the near-infrared (NIR) region in both solution and solid state, showing emission maximum at ca. 750 and 712 nm, respectively. The radiative process is assigned to an excited state with triplet metal-to-ligand charge transfer (3 MLCT) character as demonstrated by in-depth photophysical and computational investigation. Noteworthy, X-ray analysis of the binuclear complexes unravels two interligand π-π-stacking interactions yielding a doubly locked structure that disfavours flattening of the tetrahedral coordination around the CuI centre in the excited state and maintain enhanced NIR luminescence. No such interaction is present in M1-M2. These findings prompt the successful use of Cu-NIR1 and Cu-NIR2 in NIR light-emitting electrochemical cells (LECs), which display electroluminescence maximum up to 756 nm and peak external quantum efficiency (EQE) of 0.43 %. Their suitability for the fabrication of white-emitting LECs is also demonstrated. To the best of our knowledge, these are the first examples of NIR electroluminescent devices based on earth-abundant CuI emitters.
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Affiliation(s)
- Abdelaziz Jouaiti
- Laboratoire de Synthèse et Fonctions des Architectures Moléculaires, UMR7140 Chimie de la Matiere Complexe, Université de Strasbourg & CNRS, 4 rue Blaise, Pascal, 67000, Strasbourg, France
| | - Lavinia Ballerini
- Institut de Physique et Chimie des Matériaux de Strasbourg (IPCMS) UMR7504, Université de Strasbourg & CNRS, 23 rue du Loess, 67083, Strasbourg, France
| | - Hsiang-Ling Shen
- Institute of Lighting and Energy Photonics, National Yang Ming Chiao Tung University, Tainan, 71150, Taiwan
| | - Ronan Viel
- Institut de Physique et Chimie des Matériaux de Strasbourg (IPCMS) UMR7504, Université de Strasbourg & CNRS, 23 rue du Loess, 67083, Strasbourg, France
| | - Federico Polo
- Department of Molecular Sciences and Nanosystems, Ca' Foscari University of Venice, Via Torino 155, 30172, Venezia, Italy
| | - Nathalie Kyritsakas
- Service de Radiocristallographie, Fédération de chimie Le Bel - FR2010, Université de Strasbourg & CNRS, 1, rue Blaise Pascal, 67008, Strasbourg, France
| | - Stefan Haacke
- Institut de Physique et Chimie des Matériaux de Strasbourg (IPCMS) UMR7504, Université de Strasbourg & CNRS, 23 rue du Loess, 67083, Strasbourg, France
| | - Yu-Ting Huang
- Department of Applied Chemistry, Providence University, Taichung, 43301, Taiwan
| | - Chin-Wei Lu
- Department of Applied Chemistry, Providence University, Taichung, 43301, Taiwan
| | - Christophe Gourlaouen
- Laboratoire de Chimie Quantique, Institut de Chimie de Strasbourg UMR7177, Université de Strasbourg & CNRS, 4 Rue Blaise Pascal, 67008, Strasbourg, France
| | - Hai-Ching Su
- Institute of Lighting and Energy Photonics, National Yang Ming Chiao Tung University, Tainan, 71150, Taiwan
| | - Matteo Mauro
- Institut de Physique et Chimie des Matériaux de Strasbourg (IPCMS) UMR7504, Université de Strasbourg & CNRS, 23 rue du Loess, 67083, Strasbourg, France
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7
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Rosko MC, Espinoza EM, Arteta S, Kromer S, Wheeler JP, Castellano FN. Employing Long-Range Inductive Effects to Modulate Metal-to-Ligand Charge Transfer Photoluminescence in Homoleptic Cu(I) Complexes. Inorg Chem 2023; 62:3248-3259. [PMID: 36749829 DOI: 10.1021/acs.inorgchem.2c04315] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
Four Cu(I) bis(phenanthroline) photosensitizers formulated from a new ligand structural motif (Cu1-Cu4) coded according to their 2,9-substituents were synthesized, structurally characterized, and fully evaluated using steady-state and time-resolved absorption and photoluminescence (PL) measurements as well as electrochemistry. The 2,9-disubstituted-3,4,7,8-tetramethyl-1,10-phenanthroline ligands feature the following six-membered ring systems prepared through photochemical synthesis: 4,4-dimethylcyclohexyl (1), tetrahydro-2H-pyran-4-yl (2), tetrahydro-2H-thiopyran-4-yl (3), and 4,4-difluorocyclohexyl (4). Universally, these Cu(I) metal-to-ligand charge transfer (MLCT) chromophores display excited-state lifetimes on the microsecond time scale at room temperature, including the three longest-lived homoleptic cuprous phenanthroline excited states measured to date in de-aerated CH2Cl2, τ = 2.5-4.3 μs. This series of molecules also feature high PL quantum efficiencies (ΦPL = 5.3-12% in CH2Cl2). Temperature-dependent PL lifetime experiments confirmed that all these molecules exhibit reverse intersystem crossing and display thermally activated delayed PL from a 1MLCT excited state lying slightly above the 3MLCT state, 1050-1490 cm-1. Ultrafast and conventional transient absorption measurements confirmed that the PL originates from the MLCT excited state, which remains sterically arrested, preventing an excessive flattening distortion even when dissolved in Lewis basic CH3CN. Combined PL and electrochemical data provided evidence that Cu1-Cu4 are highly potent photoreductants (Eox* = -1.73 to -1.62 V vs Fc+/0 in CH3CN), whose potentials are altered solely based on which heteroatoms or substituents are resident on the 2,9-appended ring derivatives. It is proposed that long-range electronic inductive effects are responsible for the systematic modulation observed in the PL spectra, excited-state lifetimes, and the ground state absorption spectra and redox potentials. Cu1-Cu4 quantitatively follow the energy gap law, correlating well with structurally related cuprous phenanthrolines and are also shown to triplet photosensitize the excited states of 9,10-diphenylanthracene with bimolecular rate constants ranging from 1.61 to 2.82 × 108 M-1 s-1. The ability to tailor both photophysical and electrochemical properties using long-range inductive effects imposed by the 2,9-ring platforms advocates new directions for future MLCT chromophore discovery.
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Affiliation(s)
- Michael C Rosko
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, United States
| | - Eli M Espinoza
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, United States
| | - Sarah Arteta
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, United States
| | - Sarah Kromer
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, United States
| | - Jonathan P Wheeler
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, United States
| | - Felix N Castellano
- Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, United States
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8
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Interplay of electronic and geometric structure on Cu phenanthroline, bipyridine and derivative complexes, synthesis, characterization, and reactivity towards oxygen. Coord Chem Rev 2023. [DOI: 10.1016/j.ccr.2022.214943] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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9
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Appleton JL, Gourlaouen C, Ruppert R. Remote Steric Control of the Tetrahedral Coordination Geometry around Heteroleptic Copper(I) Bis(Diimine) Complexes. Molecules 2023; 28:molecules28030983. [PMID: 36770648 PMCID: PMC9920475 DOI: 10.3390/molecules28030983] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Revised: 01/10/2023] [Accepted: 01/12/2023] [Indexed: 01/21/2023] Open
Abstract
In this study, a series of new heteroleptic copper(I) bis(diimine) complexes are described. Using one highly hindered phenanthroline ligand and a second less-hindered diimine ligand led to unexpected results. Following a two-step one-pot method to obtain heteroleptic copper(I) complexes, an almost perfect tetrahedral coordination geometry around the copper(I) ion was obtained in several cases, despite the fact that at least one ligand was not sterically encumbered near the coordination site (at the position α to the nitrogen atoms of the ligand). This was demonstrated in the solid state by resolution of crystal structures, and these findings, corroborated by calculations, showed that the non-covalent interactions between the two diimine ligands present in these complexes were governing these structural features. The electronic properties of all complexes were also determined and the fluorescence lifetimes of two complexes were compared.
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10
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Beaudelot J, Oger S, Peruško S, Phan TA, Teunens T, Moucheron C, Evano G. Photoactive Copper Complexes: Properties and Applications. Chem Rev 2022; 122:16365-16609. [PMID: 36350324 DOI: 10.1021/acs.chemrev.2c00033] [Citation(s) in RCA: 50] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Photocatalyzed and photosensitized chemical processes have seen growing interest recently and have become among the most active areas of chemical research, notably due to their applications in fields such as medicine, chemical synthesis, material science or environmental chemistry. Among all homogeneous catalytic systems reported to date, photoactive copper(I) complexes have been shown to be especially attractive, not only as alternative to noble metal complexes, and have been extensively studied and utilized recently. They are at the core of this review article which is divided into two main sections. The first one focuses on an exhaustive and comprehensive overview of the structural, photophysical and electrochemical properties of mononuclear copper(I) complexes, typical examples highlighting the most critical structural parameters and their impact on the properties being presented to enlighten future design of photoactive copper(I) complexes. The second section is devoted to their main areas of application (photoredox catalysis of organic reactions and polymerization, hydrogen production, photoreduction of carbon dioxide and dye-sensitized solar cells), illustrating their progression from early systems to the current state-of-the-art and showcasing how some limitations of photoactive copper(I) complexes can be overcome with their high versatility.
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Affiliation(s)
- Jérôme Beaudelot
- Laboratoire de Chimie Organique, Service de Chimie et PhysicoChimie Organiques, Université libre de Bruxelles (ULB), Avenue F. D. Roosevelt 50 - CP160/06, 1050Brussels, Belgium.,Laboratoire de Chimie Organique et Photochimie, Service de Chimie et PhysicoChimie Organiques, Université libre de Bruxelles (ULB), Avenue F. D. Roosevelt 50 - CP160/08, 1050Brussels, Belgium
| | - Samuel Oger
- Laboratoire de Chimie Organique, Service de Chimie et PhysicoChimie Organiques, Université libre de Bruxelles (ULB), Avenue F. D. Roosevelt 50 - CP160/06, 1050Brussels, Belgium
| | - Stefano Peruško
- Laboratoire de Chimie Organique, Service de Chimie et PhysicoChimie Organiques, Université libre de Bruxelles (ULB), Avenue F. D. Roosevelt 50 - CP160/06, 1050Brussels, Belgium.,Organic Synthesis Division, Department of Chemistry, University of Antwerp, Groenenborgerlaan 171, 2020Antwerp, Belgium
| | - Tuan-Anh Phan
- Laboratoire de Chimie Organique et Photochimie, Service de Chimie et PhysicoChimie Organiques, Université libre de Bruxelles (ULB), Avenue F. D. Roosevelt 50 - CP160/08, 1050Brussels, Belgium
| | - Titouan Teunens
- Laboratoire de Chimie Organique et Photochimie, Service de Chimie et PhysicoChimie Organiques, Université libre de Bruxelles (ULB), Avenue F. D. Roosevelt 50 - CP160/08, 1050Brussels, Belgium.,Laboratoire de Chimie des Matériaux Nouveaux, Université de Mons, Place du Parc 20, 7000Mons, Belgium
| | - Cécile Moucheron
- Laboratoire de Chimie Organique et Photochimie, Service de Chimie et PhysicoChimie Organiques, Université libre de Bruxelles (ULB), Avenue F. D. Roosevelt 50 - CP160/08, 1050Brussels, Belgium
| | - Gwilherm Evano
- Laboratoire de Chimie Organique, Service de Chimie et PhysicoChimie Organiques, Université libre de Bruxelles (ULB), Avenue F. D. Roosevelt 50 - CP160/06, 1050Brussels, Belgium
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11
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Kübler J, Pfund B, Wenger OS. Zinc(II) Complexes with Triplet Charge-Transfer Excited States Enabling Energy-Transfer Catalysis, Photoinduced Electron Transfer, and Upconversion. JACS AU 2022; 2:2367-2380. [PMID: 36311829 PMCID: PMC9597861 DOI: 10.1021/jacsau.2c00442] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2022] [Revised: 09/22/2022] [Accepted: 09/22/2022] [Indexed: 05/28/2023]
Abstract
Many CuI complexes have luminescent triplet charge-transfer excited states with diverse applications in photophysics and photochemistry, but for isoelectronic ZnII compounds, this behavior is much less common, and they typically only show ligand-based fluorescence from singlet π-π* states. We report two closely related tetrahedral ZnII compounds, in which intersystem crossing occurs with appreciable quantum yields and leads to the population of triplet excited states with intraligand charge-transfer (ILCT) character. In addition to showing fluorescence from their initially excited 1ILCT states, these new compounds therefore undergo triplet-triplet energy transfer (TTET) from their 3ILCT states and consequently can act as sensitizers for photo-isomerization reactions and triplet-triplet annihilation upconversion from the blue to the ultraviolet spectral range. The photoactive 3ILCT state furthermore facilitates photoinduced electron transfer. Collectively, our findings demonstrate that mononuclear ZnII compounds with photophysical and photochemical properties reminiscent of well-known CuI complexes are accessible with suitable ligands and that they are potentially amenable to many different applications. Our insights seem relevant in the greater context of obtaining photoactive compounds based on abundant transition metals, complementing well-known precious-metal-based luminophores and photosensitizers.
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Towards Optimized Photoluminescent Copper(I) Phenanthroline-Functionalized Complexes: Control of the Photophysics by Symmetry-Breaking and Spin–Orbit Coupling. MATERIALS 2022; 15:ma15155222. [PMID: 35955157 PMCID: PMC9369739 DOI: 10.3390/ma15155222] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Revised: 07/19/2022] [Accepted: 07/21/2022] [Indexed: 11/17/2022]
Abstract
The electronic and structural alterations induced by the functionalization of the 1,10-phenanthroline (phen) ligand in [Cu(I) (phen-R2)2]+ complexes (R=H, CH3, tertio-butyl, alkyl-linkers) and their consequences on the luminescence properties and thermally activated delay fluorescence (TADF) activity are investigated using the density functional theory (DFT) and its time-dependent (TD) extension. It is shown that highly symmetric molecules with several potentially emissive nearly-degenerate conformers are not promising because of low S1/S0 oscillator strengths together with limited or no S1/T1 spin–orbit coupling (SOC). Furthermore, steric hindrance, which prevents the flattening of the complex upon irradiation, is a factor of instability. Alternatively, linking the phenanthroline ligands offers the possibility to block the flattening while maintaining remarkable photophysical properties. We propose here two promising complexes, with appropriate symmetry and enough rigidity to warrant stability in standard solvents. This original study paves the way for the supramolecular design of new emissive devices.
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